I would like to know if anybody has used a self-propelled dollie to move a camper around. I am looking at two different models right now. One is manufactured by Power Caster and the other one is a Powermaster.
I personally haven't used either, but my neighbor had one and he used it to move his 30+ foot Airstream around. Worked great.
I bought an old lawn tractor, mounted a 2" ball on the back and use it.
Wheel Skates (wheel dollies) like Harbor Freight sells, are also a good option. There's a version that grabs the wheel and lifts it off the ground, and a less expensive version that's just a metal pan on wheels and you jack up whatevery you're moving and set "it" down into the pan.
You might consider having a hitch mounted on the front of your tow vehicle. I can park my PU in a very tight space in my garage with this setup.
I've had and used the Model AC6 from http://www.powermoverinc.net for several years now. It works great. I push our 22ft HTT up a driveway and thread it through a gate with less than a foot to spare on either side, all while constantly maneuvering it through a turn and avoiding a low retaining wall on one side and a 6foot brick wall on the other. I had previously tried both backing in and using a front mounted hitch on a the TV. Both worked, but with not nearly the success I have with the Power Mover.
Power Mover is not the sharpest made or fanciest of the powered trailer dollies. But it works and it was inexpensive, IMO, compared to repairing the trailer or the roof of the house or the gates or.......